Sanamyan and Gleason, 2009 : 54Polyclinidae (Ascidiacea: Aplousobranchia) from the Gulf of Mexico, collected during the “ Hourglass ” cruises (1965 - 1967)Fortaleza, Maria Tarciana VieiraLotufo, Tito Monteiro Da CruzZootaxa201844224519536Sanamyan & Gleason, 2009Sanamyan & Gleason2009[151,721,1124,1150]AscidiaceaPolyclinidaeAplidiumGBIFAnimaliaEnterogona8527Chordataspeciesruzickai Aplidium ruzickai Sanamyan and Gleason, 2009: 54. Examined material:collected in 15/4/1966, 27°37’N, 083°07’W, 18.3 m, specimen # EJ-66-140. Description:Lobular colony measuring 6.5 x 3.0 cm, attached by a broad base with sediment included. Tunic cream colored, slightly transparent, of gelatinous consistency. Surface free of sediment or incrustations and very irregular due to the depressions that mark the zooid systems, a common characteristic in this species after the material fixation ( Sanamyan & Gleason, 2009). FIGURE 11. Aplidium ruzickai. A—thorax and abdomen; B—thorax; C—post-abdomen; D—larvae. Scale: A, B and C = 1 mm; D = 0,1 mm. Zooids elongated and opaque, average length of 10.03 mm(length range – thorax plus abdomen = 3.70–4.23 mm; post-abdomen = 3.04–8.90 mm). Branchial siphon tubular, 0.27–0.37 mmlong, six rounded lobes. Atrial opening smooth, located at the level of the fourth or fifth stigmata row. Atrial languet simple and short, measuring 0.27 mmat most. Around 20 longitudinal muscle fibers sparsely distributed parallel to the post-abdomen. Pharynx with 15 to 20 stigmata rows. The number of stigmata per row could not be counted. Esophagus long, measuring about a third of the thorax length. Stomach relatively large and strongly flattened in the posterior and anterior ends, positioned in the middle of the abdomen, with approximately 28 mostly continuous folds. The esophagus and stomach size together are more than half the abdomen length. Posterior stomach present at the posterior end of the abdomen. Anal opening at the height of the eleventh or twelfth stigmata rows. Small constriction between abdomen and post-abdomen. Zooids with well-developed gonads and a thick spermiduct. Male follicles occupying either the posterior side of the post-abdomen in a unique series or in a double series; ovary located in the middle portion of the post-abdomen, among the testicular follicles, formed by one or two large oocytes and some other smaller ones. The half posterior side of the thorax takes five to six embryos and larvae in a unique or double series. Larvae up to 0.86 mmlong, exhibiting a tail wound around more than halfway of the trunk with three adhesive papillae with long peduncles and numerous short ampullae. Presence of epidermal vesicles clustered in the anterior region of the larvae. Remarks. Aplidium ruzickaiwas recently described for the Georgiacoast ( U.S.A.). The authors observed 17 to 19 rows of stigmata in the pharynx ( Sanamyan & Gleason, 2009); however, in the material herein described, we observed 20 stigmata rows, slightly increasing the variation range of the feature for this species.